Update clients to handle GitHub Actions

cmd/bot/config.go

@@ -3,6 +3,8 @@ package main
 import (
 	"errors"
 	"fmt"
+	"log/slog"
+	"os"
 
 	"github.com/kelseyhightower/envconfig"
 
@@ -29,9 +31,10 @@ type config struct {
 
 	GitHub github.Config
 
-	IsCI  bool   `envconfig:"CI"`
-	PR    int    `envconfig:"DRONE_PULL_REQUEST" required:"true"`
-	Event string `envconfig:"DRONE_BUILD_EVENT"`
+	IsCI     bool   `envconfig:"CI"`
+	PR       int    `envconfig:"DRONE_PULL_REQUEST" required:"true"`
+	Event    string `envconfig:"DRONE_BUILD_EVENT"`
+	LogLevel string `envconfig:"LOG_LEVEL" default:"info"`
 }
 
 const pullRequestEvent = "pull_request"
@@ -60,6 +63,12 @@ func (c config) validate() error {
 		return fmt.Errorf("github configuration: %w", err)
 	}
 
+	var level slog.Level
+	if err := level.UnmarshalText([]byte(c.LogLevel)); err != nil {
+		return fmt.Errorf("parsing log level: %w", err)
+	}
+	logger := slog.New(slog.NewJSONHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelInfo}))
+	slog.SetDefault(logger)
 	// TODO check repo exists
 
 	return nil

cmd/bot/main.go

@@ -73,14 +73,17 @@ func realMain(ctx context.Context) error {
 
 	repo := git.NewRepository(cfg.Manifests.RepoPath)
 
-	oldCommit := "master"
-	newCommit, err := repo.GetCurrentCommit(ctx)
+	oldCommit, err := repo.GetCommit(ctx, "HEAD^")
 	if err != nil {
-		return fmt.Errorf("getting current commit: %w", err)
+		return fmt.Errorf("getting commit: %w", err)
 	}
 
-	rev := oldCommit + "..." + newCommit
-	cf, err := repo.ChangedFiles(ctx, rev)
+	newCommit, err := repo.GetCommit(ctx, "HEAD")
+	if err != nil {
+		return fmt.Errorf("getting commit: %w", err)
+	}
+
+	cf, err := repo.ChangedFiles(ctx, oldCommit, newCommit)
 	if err != nil {
 		return err
 	}

pkg/git/repository.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"os/exec"
 	"strings"
@@ -29,27 +30,31 @@ func (r Repository) git(ctx context.Context, args ...string) ([]byte, error) {
 
 	out, err := cmd.Output()
 	if err != nil {
+		var ee *exec.ExitError
+		if errors.As(err, &ee) {
+			return nil, fmt.Errorf("running %v: %w\n%s", cmd, ee, ee.Stderr)
+		}
 		return nil, fmt.Errorf("running %v: %w", cmd, err)
 	}
 
 	return out, nil
 }
 
-func (r Repository) GetCurrentCommit(ctx context.Context) (string, error) {
-	head, err := r.git(ctx, "rev-parse", "HEAD")
+func (r Repository) GetCommit(ctx context.Context, ref string) (string, error) {
+	head, err := r.git(ctx, "rev-parse", ref)
 	if err != nil {
 		return "", err
 	}
 
 	return strings.TrimSpace(string(head)), nil
 }
 
-func (r Repository) ChangedFiles(ctx context.Context, rev string) (ChangedFiles, error) {
+func (r Repository) ChangedFiles(ctx context.Context, oldCommit string, newCommit string) (ChangedFiles, error) {
 	cf := ChangedFiles{
 		Renamed: make(map[string]string),
 	}
 
-	out, err := r.git(ctx, "diff", "--name-status", rev)
+	out, err := r.git(ctx, "diff", "--name-status", oldCommit, newCommit)
 	if err != nil {
 		return cf, err
 	}

pkg/github/client.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"log/slog"
 	"net/http"
 	"strings"
 
@@ -32,6 +33,7 @@ func NewClient(ctx context.Context, cfg Config) (Client, error) {
 	var token = cfg.Token
 
 	if cfg.AppID > 0 {
+		slog.Info("Using GitHub app authentication")
 		t, err := ghinstallation.NewAppsTransport(
 			httpcache.NewMemoryCacheTransport(),
 			cfg.AppID,
@@ -52,6 +54,8 @@ func NewClient(ctx context.Context, cfg Config) (Client, error) {
 		}
 
 		token = tok.GetToken()
+	} else {
+		slog.Info("Using GitHub token authentication")
 	}
 
 	ts := oauth2.StaticTokenSource(&oauth2.Token{AccessToken: token})